1. Field of the Invention
The present invention relates to a positioning device for aligning and guiding two halves of a mold together. More specifically, the present invention relates to the positioning device having a bearing mechanism to facilitate aligning and guiding the two halves while reducing wear of the positioning device.
2. Description of the Related Art
In a typical molding process, two halves of a mold are closed together to define a cavity and material is injected into the cavity to form a product. During the molding process, the two halves are repeatedly opened and closed to form multiple products. Molding processes are used in many industries. In many of these industries, the products being formed must meet rigorous standards and specifications. Hence, the tolerance for misalignment between the mold halves during the molding process is generally small.
Positioning devices are used to reduce tolerances between the mold halves to form products that meet the appropriate standards and specifications for each industry. A typical positioning device comprises a first member attached to one of the mold halves and a second member attached to the other mold half. The first member has a male portion that engages a female portion of the second member when the mold halves are closed together.
The fit between the male and female portions of the members determines the magnitude of misalignment between the mold halves. In prior art positioning devices, the male portion includes a first pair of bearing surfaces and the female portion includes a second pair of bearing surfaces. The bearing surfaces of the male portion slide against the bearing surfaces of the female portion to provide a better fit when aligning and guiding the mold halves together. As a result, these bearing surfaces are susceptible to wear. Consequently, as demand for higher productivity increases, the speed of the molding process increases thereby increasing the wear along the bearing surfaces of prior art positioning devices.
Traditionally, when the bearing surfaces became worn, the positioning devices must be replaced in order to maintain proper tolerances. This results in increased cost and unacceptable delays in production. There remains opportunity to improve the positioning device in order to properly align the two halves of the mold while also extending the life of the positioning device.